Ive obtained a creep curve for some PVC (creep strain versus time) by experimental measurement at room temperature and under a constant stress of 20 MPa. Id like to use this data to calibrate a time-dependent viscoelastic material model in ABAQUS. Im following what I believe is the correct procedure in converting my creep strain data in to the normalised shear relaxation modulus (gR(t)).
However, when I put these data into ABAQUS, I get an error message because some of my normalised values are greater than 1 (which I accept is odd). I presume I must be doing something wrong with my calculations. My spreadsheet can be picked up from here:
If anyone has the time and/or inclination to have a look Id be very grateful. Any other suggestions concerning the error message would be highly appreciated.